As I looke at the band website you provided on Last F.M., they have a large selection of songs but yet only a few are availabe for free download.

I'm wondering is that just the bands preference for tracks they allow people to download or is there a limit that Last FM imposes?

If you really want people to hear it, just use as many of these options as you can. Also, do you follow any music blogs? Usually the people that write them take submissions and if they like it they'll post it on their blog. If you can manage to get your music up on a popular one, that gives you the added bonus of a respectable source recommending your music, whereas with last.fm and the likes people actually have to somehow come across your music on their own.

That's just the bands preference. I'm pretty sure there is no limit.

If you would like to include full albums for free what I would do is where the band has there info I'd include a link to a page where you can download all albums for free. Something just like a page containing links to megaupload and such.

If you sign up for Last.fm make sure you're signing up as an artist and not a user.

There is no limit for last fm, you can provide all of them for free if you wished.

MySpace, no longer allows free downloads, but a lot of others do, i would suggest you use last.fm

there are lots of site to share your music. better place is you tube